1. Field of the Invention
The present invention relates to an EGR cooler.
2. Related Background of the Invention
An EGR cooler is proposed by the Patent Document 1 given below. According to the proposed EGR cooler, a plurality of flat tubes is arranged in parallel, and both ends thereof penetrate through the respective header plates, thus structuring a core. A casing encloses the outer circumferential surface of the core to form a cooler body. A bypass pipe is laid along the cooler body. The bypass pipe and one end of the cooler body are connected via a tank, while the other end of the cooler body and the bypass pipe are connected to a tank having a gate valve.    [Patent Document 1] Japanese Patent Laid-Open No. 2007-9724